Wrapping machine



Jan. 27, 1970 O. HANSEN, JR:, ETAL.

WRAPP ING MACHINE 8 Sheets-Sheet 2 Filed Nov. 4, 1966 Jan. 27, 1970 o. HANSEN, JR., ETAL 3,491,515

WRAPPING MACHINE Filed Nov. 4, 1966 8 Sheets-Sheet 3 Jan. 27, 1970 o. HANSEN. JR, ET L 3,491,515

WRAPPING MAGHINE- Filed Nov. 4, 1966 8 Sheets-Sheet 4:

Jan-1.27, 1970- o. ANSEN, JR, ET AL 3,491,515-

WRAPPING MACHINE 8 Sheets-Sheet 6 WWW \Nm AND NNW - Q NJ Q Filed Nov. 4, 1966 Jan. 27, 1970 o. HANSEN, JR. ET

WRAPPING MACHINE 8 Sheets-Sheet '7 Filed NOV. 4. 1966 m T Q gm. as

Jan. 27, 1970 c HANSEN, JR, ET'A'L 3,491,515

WRAPPING MACHINE 8 Sheets-Sheet 8 Filed Nov. 4. 1966 UPPER UPPER ELEVATOR PLUNGER 2 ST RT MEI-L -39? -5 sHE p PKG. OFF 8 9 0 TACK EALER 5= STA 1's UP 7 sn P o SHEARING \.TACKSEALER g0 90. 95 IS JP 2 0 DM ELI.

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0 DOWN 75 52% O STF RTS N we ir-"MW TRANS "ORT a ARMS PICK UP 598 RETURN PACKAGE 2P0 DWELL DcwN 240 5 REVERSE 270 mwel. 2900 30 I 300 N6 L p DW ELL C D I 8 59 3'30 36 3 c 1 6 36 I 363 1 360 United States Patent 3,491,515 WRAPPING MACHINE Omar Hansen, Jr., and Harold W. Struver, Jr., Bluifton, and Robert F. McVicker, Anderson, Ind., assignors to Franklin Electric Co., Inc., Bluffton, Ind., a corporation of Indiana Filed Nov. 4, 1966, Ser. No. 592,078 Int. Cl. B65b 11/22, 41/12 US. Cl. 53-210 3 Claims ABSTRACT OF THE DISCLOSURE This disclosure deals with a machine for automatically wrapping articles such as foodstuffs in a protective film. The machine is capable of handling thin inexpensive films of the type referred as plastic shrink-film. The machine includes a mechanism for folding a section of the film around an article, severing the section from a film supply roll, tack sealing the ends of the film, folding the portions of the film at the sides of the article underneath the article, and finish sealing the folded portions of the film underneath the article.

This invention relates to wrapping machines, and more particularly to a machine for wrapping articles such as foodstuffs in a protective film.

There are presently on the market machines for automatically wrapping articles in a thin transparent film. Such machines are described in the Littlefield Patent No. 3,248,848 and in the copending patent application of Omar Hansen, Jr. et al., Ser. No. 363,954, filed Apr. 30', 1964, now Patent No. 3,432,987, the machines described therein being designed for use primarily as a fresh meat wrapper in a supermarket.

Cellophane has been commonly used as the protective film, and the above machines work very well with such a film. Newer materials, such as plastic shrink-film, have become available for use as the film, which are usually more desirable because they are less expensive and they provide a nicer looking package.

Accordingly, it is an object of this invention to provide an automatic wrapping machine, capable of handling a thin plastic film such as a shrink-film.

Another object is to provide a machine of the foregoing character, which is capable of wrapping articles at an increased rate of speed.

Still another object is to provide a machine of the foregoing character, including novel means for preventing an article from shifting on a movable elevator while the article is being wrapped.

Still another object is to provide a machine of the foregoing character, including novel means for preventing the film from slipping relative to an article while the article is being wrapped.

Still another object is to provide a machine of the foregoing character, including a novel tack sealer.

Still another object is to provide a machine of the foregoing character, including a novel main sealer.

Other objects and advantages of the invention will be apparent from the following description taken in conjunction with the accompanying figures of the drawings, in which:

FIG. 1 is a side elevational view of a wrapping machine embodying the invention;

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FIG. 2 is an enlarged fragmentary view of a portion of the machine;

FIG. 3 is a further enlarged view of a portion of the structure shown in FIG. 2;

FIG. 4 is a top elevational view of a portion of the structure shown in FIG. 3;

FIG. 5 is a bottom elevational view of a portion of the structure shown in FIG. 3;

FIG. 6 is an end elevational view of a portion of the structure shown in FIG. 3;

FIGS. 7 to 10' are schematic views illustrating the operation of a portion of the machine; I

FIGS. 11 to 13 are enlarged fragmentary views illustrating another portion of the machine;

FIGS. 14 to 16 are enlarged fragmentary views illustrating still another portion of the machine; and

FIG. 17 shows a timing diagram for the machine.

In general, a wrapping machine embodying the invention is generally similar to the wrapping machines described in the above-mentioned Littlefield Patent No. 3,248,848 and the copending patent application Ser. No. 363,954. A machine of this character comprises a Wrapping mechanism, an input mechanism for conveying articles to be wrapped to the wrapping mechanism, and a film supply and transport mechanism for feeding film into the wrapping mechanism, the latter mechanism wrapping the article in a section of the film and sealing the section of film around the article.

The film supply and transport mechanism comprises means for supporting a supply roll of the" film, means for transporting the film to the wrapping mechanism, and means providing a reserve supply of film between the film supply roll and the wrapping mechanism. As an article is being wrapped by the wrapping mechanism, film is drawn from the reserve supply, thereby gradually depleting it. When this reserve supply has been depleted to a predetermined length of film, a drive motor connected to the supply roll is automatically energized to feed film from the supply roll into the reserve supply to a suflicient extent to replenish the reserve supply. The drive motor is later automatically turned off when the reserve has been repleninshed, and remained off until the reserve supply has again been depleted. The film in the reserve supply is preferably maintained under tension, the means for maintaining tension also serving to switch the drive motor on and off.

The film supply and transport mechanism further includes means for vertically suspending a length of film adjacent the wrapping mechanism, the latter mechanism being operable to receive an article from the article input mechanism and position the article adjacent the length of film and above the lower or free end of the film. The article is then moved horizontally in the rearward direction against the film, causing the article to slide over a portion of the film and rest on the free end of the film. The article, and the portion of the film under it, are then moved upwardly by an elevator, which movement causes the film to be folded over the top of the article and downwardly on the forward side of the article due to the combination of the upward movement of the article and a dancer roll which pulls the film tightly over the top of the article and downwardly at its forward side. The article is then moved horizontally in the forward direction, causing the film at the forward side of the article to be drawn underneath the article and to overlap its free end, and during the forward movement of the article the film is severed. Movement of the article in the forward direction is halted momentarily while the overlapped portions of the film are over a tack sealer. After the film has been cut and the overlapped portions of the section of film have been tack sealed, the article is moved through an end folding mechanism which folds the ends of the film underneath the article and moves the article to a main sealer. After the article has passed the main sealer, it arrives at an output station which may have any desired form.

The elevator for moving the articles upwardly includes a plurality of fingers which are operable to engage the article and prevent it from being pulled off the elevator by the film while the elevator is moving upwardly. These fingers are actuated to engage and hold the article immediately after the article has been pushed onto the elevator and before the elevator has begun its upward movement, thereby preventing any possible movement of the article at any time during upward movement of the elevator. The elevator further includes a novel spring biased receiver bar which holds the film against the article and thus prevents the film from slipping relative to the article.

While the article is being moved off the elevator, the film is severed, this schedule permitting the articles to be wrapped at a relatively rapid rate. The machine further includes a novel tack sealer and a novel main sealer which seal the shrink-film around the article after the articles have been moved off the elevator.

In greater detail, the wrapping machine comprises a frame 30 (FIGS. 1 and 2) including two laterally spaced plate members 31 and 32 which are secured together by suitable braces 33 and are mounted on wheels 34 for movement on the floor. Mounted on the frame between the plate members 31 and 32 is an article input mechanism 36, a wrapping mechanism 37, film supply and transport mechanism 38 and a drive mechanism 39.

The article input mechanism 36 is shown as being in the form of a chain conveyor and includes two pairs of laterally spaced sprockets 41 and two laterally spaced chains 42 which mesh with the sprockets 41. Attached beteen the two chains 42 are a series of runners or pushers 43 which push articles placed between the chains 42 from left to right, or in the forward direction, as the chains 42 are rotated in the clockwise direction as seen in FIGS. 1 and 2. An article to be wrapped is placed on a horizontal plate 44 between a pair of laterally spaced, longitudinally extending guides 46, and between adjacent pushers 43, and one of the pushers 43 engages the article and pushes it along the upper surface of the plate 44 in the forward direction into the wrapping mechanism 37. The drive mechanism 39 is connected to rotate the sprockets 41 and the chains 42 in any conventional drive. For example, the sprockets 41 may be connected to laterally extending sha-fts 47 which are rotatably mounted on the frame 30 between the plates 31 and 32, and connected by a suitable chain and sprocket arrangement to a main drive motor of the drive mechanism 39, located generally below the input mechanism 36. It is preferred that the drive mechanism 39 be connected to drive both the input mechanism 36 and the wrapping mechanism 37 so that the rate of rotation of the chains 42 and the positions of the pushers 43 will always have a predetermined relation with the rate of operation and the positions of the parts of the wrapping mechanism 37, and consequently the two rates may be adjusted simultaneously.

The drive mechanism 39 comprises a shaft 51 which is rotatably mounted on the frame 30 and is connected to be rotated by a drive motor (not shown). A sprocket may be fastened to the shaft 51 in order to drive the input mechanism 36 as previously explained. In addition, three earns 52 are secured to the shaft 51, one of the cams being connected by a follower mechanism 53 to move a pair of elevators, another of the cams being connected by a follower mechanism 54 to move a plunger mechanism, and the third of the three cams being connected by a follower mechanism 56 to move a film severing blade.

The film, indicated by the reference numeral 61 in FIGS. 1 to 3, for wrapping an article, is delivered to the wrapping mechanism 37 by the film feed and transport mechanism 38 which comprises an arbor 62 (FIG. 1) for supporting a supply roll 63 of film, the arbor 62 being connected to be driven by a motor-gear box unit 64. As described in detail in the copending Hansen et al. patent application, the arbor 62 may comprise a cylindrical tube 66, the outer diameter of which is slightly less than the inner diameter of the supply roll 63 so that the roll 63 may easily be slipped over the arbor 62. The tube 66 is connected to the motor-gear box unit 64 by a drive shaft (not shown) and is supported by a mounting plate 68. The plate 68 is secured to the frame of the machine, and the motor-gear box unit 64 is secured to one side of the plate 68 while the tube 66 extends laterally of the machine from the other side of the plate 68. Means (not shown) is also provided to releasably lock the supply roll 63 on the tube 66 so that the tube 66 and the supply roll 63 may be driven as a unit by the drive motor 64.

The supply roll 63 is mounted such that the free end of the film 61 extends upwardly from the forward side of the roll 63, and the film is threaded from the roll 63 upwardly and rearwardly of the machine under and around the rearward side of a laterally extending roller 71 which is secured to the frame of the machine, over the top of the roller 71 and forwardly of the machine, under and around the forward side of a tension roller 72 (FIG. 1) over the top of the roller 72, and then rearwardly of the machine and over the top of two laterally extending rollers 73 and 74 which support the film in a substantially horizontally extending plane.

As explained in the previously mentioned Hansen et al. application, the tension roller 72 extends laterally of the machine and is rotatably mounted at the upper ends of two laterally spaced tension arms or levers 76 which are fastened to and rotate with a shaft 77. The shaft 77 is also rotatably supported by the mounting plate 68, and one end of the shaft 77 carries a cam (located on the side of the plate 78 which is not shown in FIG. 1). The cam is connected to actuate a switch for controlling the motor-gear box unit 64. The cam and switch arrangement is such that the unit 64 is turned on when the arms 76 swing in the counterclockwise direction and reach a first predetermined position, and the unit 64 is turned off when the arms 76 swing in the clockwise direction and reach a second predetermined position. A spring (not shown) urges the arms 76 in the clockwise direction thereby maintaining tension on the film, and a pull on the film during a wrapping cycle urges the arms 76 in the counterclockwise direction. During the operation of the machine, the film 61 is drawn into the wrapping mechanism as each article is being wrapped and the consequent pull on the film 61 swings the tension roller 72 and the arms 76 in the counterclockwise direction as seen in FIG. 1. When the shaft 77 and the arms 76 reach the first predetermined angular position, the cam attached to the end of the shaft 77 closes the control switch for the motor-gear box unit 64. Upon energization of the unit 64, the arbor '62 is driven to turn the supply roll 63 in the counterclockwise direction as seen in FIG. 1.

From the tension roller 72, the film 61 is threaded over the top of the two rollers 73 and 74 and underneath a one way check mechanism 78 (FIGS. 2 and 3) which is mounted on the frame of the machine over the upper surface of the roller 74. The check mechanism 78 permits movement of the film 61 in the rearward direction but pinches the film 61 against the roller 74 when there is a tendency for the film 61 to move forwardly, as when the film 61 is pulled by the tension roller 72 and the tension arms 76. When the wrapping machine is idling between packages, the film 61 normally extends downwardly around the rearward side of the shaft 74, past the forward side of a dancer roller 81 (FIG. 3) and between bottom and top elevators 82 and 83. The free end portion of the film 61 is held by a suction bafile plate 84 which extends laterally of the machine and is secured to the frame as by brackets 86. The baffle plate 84 comprises a vertically extending back 87 and a horizontal shelf 88 which extends rearwardly from the lower edge of the back 87. The shelf 88 has a hollow interior which forms a suction box, each end of the shelf 88 being connected by a length of hose 89 (FIGS. 1 and 2) to means, such as a motor driven fan 91 (FIG. 1) for producing a partial vacuum. The top side of the shelf 88 has sets of holes formed therein, and air is drawn into the interior of the hollow shelf 88 through the holes. This suction draws the film 61 to the shelf 88 and holds the free end portion of the film 61 flat against the shelf 88 as shown in FIG. 3, thereby preventing curling of the free end of the film 61 and also preventing curling of the vertical edges of the film adjacent its free end.

The wrapping mechanism 37 comprises the bottom elevator 82 and the top elevator 83 which are supported by two pairs of arms or bars 101 and 102 (FIG. 3), one bar of each pair being shown in FIGS. 1 to 3. One bar of each pair is pivotally connected to one side of each of the elevators 82 and 83, and at substantially their centers the bars 101 and 102 are also pivotally connected to the frame of the machine as by pins 103 (FIG. 1). At least one, and preferably two, vertically extending links 104 (FIGS. 1 and 2) are provided, which extend downwardly from the lower bars 101 and are connected to the cam follower mechanism 53 to be moved substantially vertically in a reciprocating motion by the drive mechanism 39 which, as previously stated, is preferably also connected to drive the input mechanism 36. The cam follower mechanism 53 comprises a triangular shaped plate 106 which is mounted at one corner on a shaft 107. Another corner of the plate 106 has a cam follower 108 fastened thereto, and the third corner of the plate 106 is connected to a link 104 by a pin 109. Thus, when the shaft 51 and the face cams 52 are rotated, the plate 106 pivots about the axis of the shaft 107, causing the link 104 and the elevators 82 and 83 to move up and down in a reciprocating motion.

Movement of the link 104 causes the two elevators 82 and 83 to swing between horizontally aligned, intermediate positions shown in FIG. 1, in dashed lines, and vertically displaced positions shown in full lines in FIG. 3. The elevators 82 and 83 have substantially flat plates 116 and 117, respectively, which form article supporting surfaces and which are always horizontal because the bars 101 and 102 form parallel arms. When the elevators 82 and 83 are at the intermediate position, the plates 116 and 117 are at substantially the same level, as shown in dashed lines in FIG. 1. When the elevators 82 and 83 are at the vertically displaced positions, the upper surface of the plate 116 is substantially at the level of the upper surface of the plate 44 of the input mechanism 36, and the upper surface of the plate 117 of the elevator 83 is substantially at the level of a support 118 (see FIG. 2) of an end folding and sealing apparatus 119 of the wrapping mechanism 37.

The wrapping mechanism 37 further includes plunger means for moving an article being wrapped from the bottom elevator 82 to the top elevator 83 when the two elevators are at the intermediate position, and also for moving the article from the top elevator 83 to the support 118 when the two elevators are in the vertically displaced positions. As described in the previously mentioned Hansen et al. patent application, the plunger means comprises a top plunger 121 and a bottom plunger 122. The top plunger 121 is fastened to a slider 123 which is movable longitudinally of the machine on a suitable guide means 124, while the bottom plunger is mounted on another slider 126 which is also mounted for longitudinal movement on the machine on another guide means 127.

A link 128 extends between and is connected to the two sliders 123 and 126, and the link 128 is connected to the cam follower mechanism 54 for periodically moving the sliders 123 and 126, and the plungers 121 and 122 attached thereto, longitudinally of the machine in synchronism to move the articles as previously described. The link 128 is pivotally connected by a pin 131 (FIG. 2) to one corner of a three cornered plate 132 which is pivotally connected by another pin 133 at another corner to the frame of the machine. The third corner of the plate.132 is connected by a pin 134 to a link 136 which extends downwardly therefrom to another plate 137 (FIG. 1) of the follower mechanism 54. The plate 137 is pivotally mounted by a pin 138 on the frame of the machine, it is connected by a cam follower 139 to one of the three face cams 52, and it is connected by a pin 141 to the link 136. Rotation of the shaft 51 and the cams 52 causes the plate 137 to pivot or rock about the axis of the pin 138, thus causing the link 136 to move up and down with a reciprocating motion. Such movement of the link 136 causes pivotal or rocking movement of the plate 132 about the pin 133 and, consequently, reciprocating movement of the plungers 121 and 122. Since the cams 52 rotate together on the shaft 51, the movement of the plungers 121 and 122 is synchronized with the movement of the two elevators 82 and 83. When the two elevators are at the intermediate position, the two plungers 121 and 122 move toward the left, or rearwardly, as seen in FIGS. 1 and 2, the plunger 122 moving an article from the bottom elevator 82 to the top elevator 83, and when the two elevators are in the vertically displaced positions, the two plungers 121 and 122 move toward the right, or forwardly, the plunger 121 moving an article from the top elevator to the support 118.

The bottom plunger is preferably in the form of a rake, having a plurality of downwardly extending teeth which sweep across the upper surface of the plate 116 of the bottom elevator 82 and engage the rearward side of an article being wrapped when the plunger 122 is moved rearwardly, in order to move in article from the bottom elevator to the top elevator. The top plunger 121 may be a simple rod like member which angles downwardly and forwardly as shown in FIGS. 1 and 2, the lower end of the plunger 121 being at substantially the lateral center of the plate 117 of the top elevator 83.

The top elevator 83 is provided with a spring biased longitudinally movable receiver bar 146 which prevents the film from slipping relative to the article while the article is on the top elevator. The plate 117 comprises two laterally spaced sections 117a and 117b (FIG. 4), the space 147 between the two sections being located midway between the sides of the plate 117. The receiver bar 146 comprises a generally rectangular block 148 (FIGS. 3 and 4) which is connected to the plate 117 by nut and bolts 149, the bolts extending through the space 147 and through another block 151 located on the underside of the plate 117. An angle shaped bracket 152 is secured to the forward side of the block 148 one arm of the bracket extending generally vertically and the other arm of the bracket being positioned to extend under the botom of an article being wrapped adjacent its rearward edge, and a pad 153 of friction material is preferably secured to the forward side of the vertical arm of the bracket 152. To prevent the film from slipping relative to an article, the receiver bar 146 is spring biased in the forward direction in order to hold the friction pad 153 against the portion of the film at the rearward side of an article, by means comprising a torsion spring 154 (FIG. 4) coiled around a laterally extending shaft 156 which is secured to the top elevator 83 underneath and at the rearward edge of the plate 117. One end 157 of the shaft 156 is rotatably connected to the elevator 83 while the other end 158 is secured to a bracket 159 by a set screw 161. One end 162 of the torsion spring 154 is secured to the shaft 156 while the other end 163 is secured to a drum 164 which is rotatably mounted on the shaft 156. A cord 166 has one end secured to the outer periphery of the drum 164, and from the drum 164 the cord 166 extends forwardly and is looped upwardly about a small pulley 167, and then rearwardly to the block 148. The pulley 167 is rotatably mounted on the elevator 83 underneath the forward edge of the plate 117. The cord 166 extends rearwardly from the pulley 167 through the space 147, underneath the bracket 152, and then upwardly between the block 148 and the bracket 152, and a knot 168 formed in the end of the cord 166 holds the cord between the block and the bracket. To bias the block 148 forwardly, the set screw 161 on the bracket 159 is loosened and the shaft 156 is turned in order to tension the spring 154, and thereafter the set screw 161 is tightened to hold the shaft 156 stationary. The tension on the spring is such as to rotate the drum 164, and thereby wind up the cord 166 on its outer periphery, and pull the block 148 forwardly. The amount of the forwardly acting force on the block 148 may be adjusted by turning the shaft 156 such that, even if an article were to shift forward slightly, the block 148 would also move forwardly and hold the pad 153 against the portion of the film at the rearward side of the article. Thus, the article is held on the top elevator by fingers at its forward side, as will be explained hereinafter, and the receiver bar at its rearward side, and the portion of the film at the rearward side of the article is pinched between the article and friction pad 153. Thus, both the article and the film are prevented from slipping while the top elevator is moving upwardly. As will be described here inafter, when an article being wrapped is pushed by the bottom plunger 122 from the bottom elevator 82 to the top elevator 83, the rearward side of the article engages the receiver bar 146 and pushes it rearwardly of the machine and, subsequently, when the article is pushed by the top plunger 12 1 forwardly of the machine, the plunger 121 engages the block 148 and pushes it and the article toward the right, or forwardly, until the article is deposited on the support 118.

As described in the previously referred to Hansen et a1. patent application, mounted on the upper surface of the plate 117 of the top elevator 83 are a pair of laterally spaced end folders 181, which are laterally adjustable relative to the plate 117 depending upon the width of the article lbeing wrapped. The folders 181 are shaped to engage the film at the iateral ends of the article and fold the at the ends of the article as the article is being pushed from the bottom elevator 82 to the top elevator 83. The lateral adjustment may be made by a mechanism (not shown) which engages a member 182 attached to the rearward end of each of the end folders 181. The bottom elevator 82 is provided with laterally adjustable guides 183 (FIG. 3) and members 184 are attached to the guides for making a lateral adjustment. A handwheel 186 (FIG. 1) is provided which is connected by a chain and sprocket arrangement to the members 182 and 184 so that simultaneous adjustments may be made.

As the top elevator 83 is being moved upwardly during a wrapping cycle, the film is stretched tightly across the upper surface of the article and there is a tendency for the taut film to pull the article forwardly off of the plate 117 of the top elevator. To prevent the article from being pulled ofi the elevator, two rake-like brackets 191 (FIGS. 3 to are provided, one bracket being associated with each section of the plate 117 and each bracket having a plurality of generally vertically extending stop fingers 192 (FiGS. 3 and 4) which are located adjacent the forward edge of the associated section of the plate of the top elevator. Each bracket 191 is mounted underneath the plate 117, for pivotal movement relative to the top elevator, by means of a shaft 193 (FIG. 3), and a tension spring 194 is connected to urge the fingers 192 in the counterclockwise direction as seen in FIG. 3, or upwardly. Slots are formed in the forward edge of the plate 117 and the fingers 192 normally extend through these slots.

As seen in FIG. 5, the shaft 193 on which the two brackets 191 are mounted, is fastened to the underside of the sections 117a and 11712 of the plate 117 by two mounting members 196, and the spring 194 is connected to an arm 197 which is rigidly secured to one end of the shaft 193. The arm 197 extends both forwardly and rearwardly from the shaft 193-, the rearward end of the arm 197 being connected to one end of the tension spring 194. The other end of the tension spring 194 is connected to a pin 198 which in turn is fastened to the underside of the top elevator 83.

During the operation of the machine, when a package has been positioned on the top elevator 83 and the top elevator is moving upwardly, the shaft 193 is in a position where the fingers 192 extend upwardly above the upper surface of the plate 117, as shown in FIG. 2.

To retract the fingers 192 below the upper surface of the plate 117 so that the article may be moved off the top elevator 83 and on the support 118, a stationary bumper or top actuator 201 (FIGS. 3 and 6) is fastened to the frame of the machine at a location where it engages the arm 197 and causes the shaft 193 to pivot slightly when the top elevator 83 arrives at the uppermost position. As previously stated, the arm 197 extends forwardly from the shaft 193, and a portion 203 at the forward end of the arm 197 is engaged and turned by the actuator 201. The actuator 281 is stationary, and upward movement of the top elevator 83 results in downward pressure on the portion 203 and causes the arm 197 to pivot in the clockwise direction as seen in FIGS. 2 and 3 against the force of the tension spring 94, such pivotal movement of the arm 197 and the shaft 193 being sufficient to retract the upper ends of the fingers 192 below the upper surface of the plate 117.

A catch mechanism 206 (FIG. 4) is also provided to hold the fingers 192 in the retracted positions while the top elevator 83 is moving downwardly and while another article is being pushed on the top elevator 83. The trip mechanism 206 includes a longitudinally movable trip member 207 (FIG. 4) movably mounted on the underside of the plate or sheet 117 adjacent the forward portion 203 of the arm 197. The trip member 207 is fastened to a holder 208, and a coiled compression spring 209 located between an upturned forward end portion 211 of the trip member 207, and the holder 208 urges the trip member 207 forwardly. As best shown schematically in FIGS. 7 to 10, the lower edge of the end porition 211 of the trip member 207 is located to extend over the portion 203 of the arm 197 when the portion 203 has been pivoted downwardly due to engagement with the actuator 201. As shown in FIG. 8, when the portion 203 has been moved downwardly, the spring 209 moves the trip member 207 forwardly, causing the forward end portion 211 to move over the portion 203 of the arm 197, thus holding the arm 197 the pivoted position. The trip member 207 thus holds the arm 197 and the fingers 192 in the pivoted position where the upper ends of the fingers 192 are retracted below the upper surface of the plate 117 (FIG. 3) while the top elevator 83 is moving downwardly and while another article is being moved from the bottom elevator 82 onto the top elevator 83 by the bottom pusher 122.

To release the trip mechanism after an article has been pushed onto the top elevator, an actuator finger 212 (FIGS. 1 and 2) is attached to the carriage 126 which carries the bottom pusher 122. The finger 212- is located to engage the trip member 207 and push the trip memher 207 rearwardly immediately after the article has been transferred from the bottom elevator to the top elevator, such rearward movement of the trip member 207 (FIGS. 9 and 10) causing it to disengage the portion 203 of the arm 197. Thereupon, the arm 197 pivots due to the action of the spring 194, and the fingers 192 move upwardly with a snap action. Thus, the fingers 192 snap upwardly immediately after the article has been transferred to the top elevator and before the top elevator beings its upward movement. Such a snap action before the top elevator begins to move is desirable because it eliminates any possibility that either the film or the spring biased receiver bar may move the package even during initial upward movement of the elevator. It is necessary for the fingers of the bottom pusher to move rearwardly and extend over the forward edge of the plate 117 to ensure that the article will be completely on the top elevator and past the fingers 192. The cam of the main drive which moves the plungers is therefore constructed to retract the fingers of the bottom plunger a short distance immediately after an article has been deposited on the top elevator.

FIGS. 7 to 10 illustrate schematically the operation of the fingers 192. FIG. 7 shows the fingers 192 in a retracted position where they are held by the trip member 207 (FIG. 8) which extends over the portion 203 of the arm 197. In FIG. 9 an article has been transferred to the top elevator by the bottom plunger and the actuator finger 212 has engaged the trip member 207 and pushed it rearwardly (-FIG. 10) permitting the portion 203 of the arm 197 to swing upwardly, the fingers 192 thereupon snapping upwardly and extending over the forward side of the article. Thus, the article and the portion of the film extending across the rearward side of the article are tightly held between the fingers 192 and the receiver bar 148, which is spring biased toward the fingers 192. Such holding of the film and the article prevents the article from moving, and it prevents the portion of the film which extends across the rearward side of the article from slipping relative to the top elevator and the article while the top elevator is moving upwardly.

The wrapping mechanism 56 further includes scissorlike means for severing the film during each wrapping cycle. The severing means comprises a horizontal, laterally extending stationary blade 221 (FIGS. 2 and 3) which is fixed to the frame of the machine just below and forwardly of the forward edge of the support 118. The severing means further includes a pair of movable blades 222 carried by the top elevator 83 on the underside thereof and at the forward edge. The movable blades 222 are carried by brackets 223 and a shaft 224 (FIG. which extends laterally of the machine. As described in the copending Hanen et al. application, the two blades form a V with the apex of the V being toward the left a seen in FIG. 3 and at substantially the lateral center of the top elevator 83. From the apex, each of the blades 222 extends laterally of the machine and forwardly, and each of the blades also slopes downwardly a slight amount from its apex. When the top elevator 83 moves to its upper position, the outer lateral ends of the blades 222 contact the underside of the stationary blade 221, and when the shaft 224 and the blades 222 are moved forwardly, the downward and rearward slant of each of the blades 222 causes the movable blades to be in point-to-point contact only with the stationary blade 221. This produces a scissors-like action which prevents tearing or pulling of the film while it is being severed. The shaft 224 is fastened to the top elevator, 83 and a tension spring 226 is connected between a rearwardly extending end 227 of one of the brackets 223, and the pin 198, the spring 226 urging the brackets 223 and the blades 222 upwardly, or in the counterclockwise direction, as seen in FIG. 3.

The shaft 224 is also mounted for longitudinal movement relative to the top elevator 83, and after the top elevator 83 has moved to its upper most position and as an article on the top elevator is being pushed forward- 1y by the plunger 121, the shaft 224 and the blades 222 are moved forwardly to sever the section of film around the article. The mechanism for moving the shaft 224, and consequently the blades 222, longitudinally of the machine comprises a suitable cam 231 (FIGS. 2 and 3) and a cam follower 232 at each side of the top elevator, which are connected to the main drive mechanism 39 (FIG. 1). Each cam follower 232 is attached to the rearward end of an actuator rod 233, the two actuator rods 233 being mounted for longitudinal movement on the sides of the top elevator 83. The forward end of the two actuator rods 233 are connected to the ends of the shaft 224 which carries the movable cutting blades 222 and, consequently, longitudinal movement of the two rods 233 results in coresponding movement of the shaft 224 and the blades 222. As shown in FIGS. 2 and 3 each cam 231 has a cam groove or slot 234 formed therein which receive the associated cam follower 232. The lower ends of the cams 231 are secured to the opposite ends of a laterally extending shaft 236 mounted on the frame of the machine, and an actuator arm 237 is also secured to the shaft 236 which, when the arm 237 is pivoted, causes the two cams 231 to simultaneously pivot or rock about the axis of the shaft 236. Both of the cams 231 have an arcuate shape as shown in FIGS. 2 and 3, such shape being necessary because the top elevator 83 and the cam followers 232 carried thereby travel in an arcuate path while moving between the intermediate position shown in dashed lines in FIG. 1 and the uppermost position shown in FIG. 3.

The actuator arm 237 is connected by a link 238 to be pivoted or rocked by the cam follower mechanism 56 shown in FIG. 1. This latter mechanism 56 comprises a cam follower arm 239 which has one end pivotally connected to the shaft 107. The other end of the arm 239 carries a cam follower 241 which engages one of the three face cams 52. The link 238 (FIG. 2) extends from the arm 237 to a pin 240 on the arm 239 which is approximately midway between the shaft 107 and the follower 241, and as the shaft 51 and the cams 52 are rotated during each wrapping cycle, the arm 239 rocks about the axis of the shaft 107 and causes the link 238 to move up and down in a reciprocating motion. When the top elevator 83 reaches its uppermost position and the article is being pushed from the top elevator onto the support 118, the cam follower mechanism 56 causes the cams 231 to pivot slightly in the clockwise direction as seen in FIGS. 2 and 3. At this portion of the wrapping cycle, the cam followers 232 are adjacent the upper ends of the two cams 231, and the pivotal movement of the cams 231 causes the rods 233 to shift forwardly slightly. Such forward movement of the rods moves the knife blades 222 forwardly to sever the film, and, as will be explained hereinafter, to release the dancer roller 81. Thereafter, the cam follower mechanism 56 causes the cam 231 and the rods 233 to return to their normal position where the movable blades are retracted from the stationary blade. As will be explained in more detail hereinafter, the movable cutting blades are actuated to sever the film while the article is still being moved from the top elevator to the support 118, such as schedule of operation reducing the amount of time required to wrap an article, as compared with a schedule Where the film is not severed until the article has come to a stop and the film has been tack sealed.

The dancer roller 81 extends laterally of the machine and is mounted between two pairs 251 and 252 of vertically extending guides the pair 251 of guides being located at one side of the machine and the pair 2520f guides being located at the other side of the machine. The guides of each pair are longitudinally spaced to form a vertical slot 253 therebetween at each side of the machine, and the ends of the dancer roller 81 extend into the slots 253. The dancer roller 81 is vertically movable within the slots 253 and, during different portions of each wrapping cycle, is supported either by a pair of lifts 256, a pair of stationary stops 257, or a pair of movable stops 258 (FIG. 6).

As shown in FIGS. 2 and 3, the two lifts 256 are secured to the bottom elevator 82 at the sides thereof and extend upwardly and rearwardly from the plate 116. As shown in FIG. 6-, the two lifts 256 are spaced laterally inwardly from the guides 251 and 252, and the upper ends of the two lifts 256 are adapted to engage the dancer roller 81 adjacent its ends and lift the dancer roller 81 upwardly upon movement of the bottom elevator 82 to the intermediate position. Such upward movement of the dancer roller 81 during each wrapping cycle is necessary because the dancer roller 81 must be moved out of the way to permit an article to be transferred from the bot tom elevator 82 to the top elevator 83 while the two elevators are at the intermediate position. Resilient bumpers 259 are preferably secured to the upper ends of the two lifts 256 to cushion the impact of the lifts 256 with the dancer roller when the lifts 256 move upwardly and engage the dancer roller.

The two stationary stops 257 are secured to the guides 251 on the laterally inner sides thereof, as shown in FIG. 6. Again, a cushion 261 is preferably secured to the upper end of each of the stationary stops 251 in order to cushion the impact of the dancer roller 81 when the dancer roller drops downwardly onto the stationary stops 257. As shown in FIGS. 3 and 6, the stationary stops 257 are constructed such that the cushions 261 slant downwardly and extend across the guide slots 253 at locations such that the dancer roller 81, while resting on the stationary stops 257, is spaced a short distance above the shelf 88 of the suction baffle plate 84. The cushions 261 of the two stationary stops 257 are preferably slanted in order to reduce bounce of the dancer roller 81 when the dancer roller 81 drops downwardly onto the stationary stops 257.

The movable stops 258 form part of the lower ends of a pair of vertically extending levers 266 (FIG. 6), each of the levers 266 being associated with and positioned on the laterally outward side of a pair of the guides. Each lever 266 extends partially into a slot 253 from the outside thereof, and is mounted for pivotal movement on the associated guides by a longitudinally extending pin 267. Each lever 266 may be pivoted from one position, shown in FIG. 6, where the stop 258 extends into the path of the adjacent end of the dancer roller 81, and another position where the stop 258 is out of the path of the end of the dancer roller 81, and therefore may permit the dancer roller 81 to drop downwardly.

The levers 266 are normally held in the position where the stops are in the path of the dancer roller 81, by leaf springs 291 (FIG. 4). One end of each of the leaf springs 291 is secured to the frame of the machine by means of a block 292, and the other end of each of the leaf springs 291 extends over the laterally outer side of the associated lever 266 and urges the lower end of the associated lever 266 laterally inwardly. A stop pin 293 is preferably secured to each of the levers 266 adjacent its lower end at a location where the pin may engage the guides 251 and limit the extent of inward pivotal movement of the associated lever 266.

Assuming the portion of a wrapping cycle where the dancer roller 81 is being supported by the lifts 256 and the bottom elevator 82 is moving upwardly, the ends of the dancer roller 81 move upwardly and engage the stops 258. As shown in FIG. 6, the laterally inner surfaces of the stops 258 are slanted upwardly and laterally inwardly as at 294, such slant causing the levers to be pivoted outwardly against the action of the associated spring 291 as the dancer roller 81 is moved upwardly past the stops 258, whereupon the springs 291 return the levers 266 to the positions shown in FIG. 6. Subsequent downward movement of the bottom elevator 82 also permits downward movement of the dancer roller 81 until the ends of 12 ing pin 296 which is rotatably mounted in each block 291. A finger 297 is secured to the lower end of each pin 296, the finger 297 extending normal to the pin 296 and into a hole 298 in the associated lever 266, and it will be apparent that when the pin 2% shown in FIG. 4 is turned about itsaxis in the counterclockwise direction the finger 297 will engage the lever 266 and pivot the lever to move the lower end of the stop 258 out of the path of the dancer roller 81. A second finger 299 is secured to the upper end of each shaft 296, the pin 299 extending substantially laterally inwardly from the shaft 296 and in the path of the forward ends 301 of the rods 233 which also move the cutting blades 222. Thus, when the rods 233 are moved forwardly to sever the film, the forward ends of the rods 233 also engage the fingers 299 and pivot the pins 296, such pivotal movement of the pins 296 causing turning movement of the fingers 297 and thereby releasing the dancer roller 81. Subsequent retraction of the rods 233 and the cutting blades also permits the springs 291 to return the levers to the positions shown in FIG. 6 in preparation of the next wrapping cycle.

The dancer roller 81 may comprise a solid shaft of metal, the outer surface of the shaft preferably being sandblasted to produce a rippled surface. Such a surface is advantageous because the surface area in contact with the film is thereby reduced and, consequently, there is less tendency for the film to stick to the dancer roller. Other parts of the machine which engage the film such as the top elevator and the film folders, are also preferably sandblasted for the same reason.

During each wrapping cycle the plunger 121 moves forwardly of the machine and pushes an article from the top elevator 83 forwardly onto the support 118. During such forward movement of the article, the film 61 is folded underneath the article and portions of the film overlap, and adjacent the rearward end of the support 118 is provided a laterally extending tack sealer 311 (FIGS. 2, 6, ll, 12 and 13) which tack seals the overlapped portions of the film after the article has come to a stop.

As shown in FIGS. 11 to 13, the tack sealer is supported by an angle 312 and two end support members 313, the angle 312 and the members 313 being mounted on the frame of the machine. The angle 312 is positioned with one arm 314 extending generally vertically and its other arm 316 extending forwardly from the lower end of the vertical arm 314. The end support members 313 are secured to the angle 312 and extend forwardly and downwardly therefrom, the roller 74 (FIGS. 2 and 11) being rotatably mounted between the two support members 313. The tack sealer 311 comprises an electrical resistance wire 317 which extends laterally of the machine and is supported on a bar 318 made of an electrical insulating material. The resistance wire 317 may be made of Nichrome and the bar 318 may be made of a phenolic laminate. Two screws 319 and 321 are threaded into the upper side of the bar 318 at the ends thereof, and the two screws 319 and 321 are angularly positioned so that the screw driver receiving slots formed in their head are in alignment. The wire 317 has a diameter which is slightly less than the width of the screw slots and the wire 317 is positioned within these slots, as shown in FIGS. 11 and 12. A tension spring 322 is fastened between each end of the wire 317 and an end support block 313, the springs 322 serving to stretch the wire between the screws and to retract the bar and the wire after they have been raised as will be explained hereinafter. The wire 317 is connected by any suitable means to a source of electric energy and a thermostatic control.

The bar 318 is mounted for vertical movement relative to the angle 312 by means of a shaft 323 which extends laterally of the machine forwardly of the wire support bar 318, the shaft 323 being rotatably mounted and supported by the two support members 313. The wire support bar 318 is preferably connected to the shaft 323 by a single screw or pin 324 located substantially midway between the ends of the bar 318, the pin 324 extending through the shaft 323 and into the bar 318. The bar 318 is free to pivot slightly on the pin 324 and therefore even though the shaft 323 remains stationary, the bar 318 and the wire 317 may tilt slightly in one direction or the other in order to conform to the plans of the bottom of a package.

The wire 317 is normally below the upper edge of the vertical arm 314 of the angle 312 (FIG. 12) and the wire 317 is raised vertically each time a package is positioned over the wire. The wire 317 may be raised by means of an arm 326 which is secured to one end of the shaft 323. As shown in FIGS. 11 and 12, the arm 326 normally extends substantially vertically upward from the shaft 323 and it is located to be engaged by a block 327 (FIGS. 1 and 2) secured to the link 128 Which extends between the two plungers 121 and 122. It will be recalled that the link 128 moves forwardly as the upper plunger 121 is pushing an article from the top elevator 83 onto the support 118, and during this forward movement the block 327 engages the arm 326 and pivots it in the clockwise direction as seen in FIG. 12, such pivotal movement of the arm 326 causing the shaft 323 to turn and raise the bar 318 and the wire 317. The arm 326 and the block 327 are located such that the wire 317 starts to rise just after the cutting blades have severed the film and just before the package is completely pushed ofl? of the top elevator by the top plunger 121. The wire 317 normally remains up approximately one-half second until the cam follower mechanism 54 retracts the top plunger 121. Just as the wire 317 starts to move downwardly due to the action of the springs 322, a transfer arm of the and folding apparatus engages the package and pushes it across the support 118, the two elevators 82 and 83 also completing their movement toward the intermediate position almost simultaneously with the foregoing.

The electrical resistance wire 317, of course, is heated due to the passage of current through it, and the current is adjusted to produce just the right amount of heat to seal the overlapped portions of the film underneath the article. The wire 317 loses some of its heat in each sealing operation, and the use of a wire as described is advantageous becasue the wire may be rapidly reheated before the next tack sealing operation. This is advantageous as compared with a broader heating element, such as a flat band, because a substantial amount of heat would be drawn from a hand during each sealing operation and it would be difiicult to reheat the band before the next tack sealing operation. Instead of a wire, a relatively thick vertically movable shaft having a narrow bead extending laterally of the machine across the upper surface of the shaft may be provided, the fine bead being the only portion of the heating element which engages the article. Such a construction would be advantageous because after heat is drawn from the bead to seal a package, the heat is quickly replenished from the large amount of stored heat in the shaft.

The construction of the tack sealer has a further advantage because the vertical arm 314 of the angle 312 of the tack sealer protects the wire 317 while an article is being pushed from the top elevator over the tack sealer and this orientation of the angle permits the wire 317 to be positioned as far rearwardly as possible, this being advantageous because it substantially eliminates any loose film tail at the severed end of the film.

tion to the support 118, there is also provided two side supports 341 (FIGS. 14 and 15). Thus, the support 118 supports the center area of an article being wrapped While the side supports 341 support the side edges of the article.

The apparatus 119 further comprises a plurality of transport arms 342 (FIGS. 1, 2 and 15), the transfer arms 342 being arranged in pairs of laterally spaced arms. The transfer arms 342 are attached to a pair of laterally spaced chains 343 which are trained around a pair of laterally spaced sprockets 344 and two pairs of stationary disks 346 and 347. The sprockets 344 are secured to a shaft 348 which is also secured to a drive sprocket 349, the latter sprocket being connected by a suitable chain arrangement 351 to be driven by the main drive 39 of the wrapping machine. Thus, the main drive 39 continuously turns the sprocket 349 and the shaft 348 and causes the two chains 343 to travel in the counterclockwise direction as seen in FIGS. 1 and 15. The stationary disks 346 and 347, which may be made of a phenolic compound, are sufficiently thin that they extend between the links of the chains 343 as shown in FIG. 16, they support the chains 343 at the forward and rearward ends of the transport mechanism. Guides 352 are also provided to hold the chains 343 at the edges of the sprockets 344 and the disks 346 and 347.

The timing of the machine is such that a pair of transport arms 342 moves to a position adjacent the rearward edge of the support 118 after each article has been pushed from the top elevator 83 on to the support 118. As previously stated, the timing is preferably such that the article is momentarily stationary while the article is over the tack sealer 311, thereby giving the tack sealer sufficient time to heat and seal the overlapped portions of the film. The transport arms 342 move the articles forwardly across the supports 118 and 341 and through a plurality of end folding plates 353, which are described in greater detail in the previously mentioned copending Hansen application and partially shown in FIGS. 2, 14 and 15. The end folding apparatus draws the film tightly in the lateral direction and folds the ends of the film underneath the article.

After an article is pushed through the end folding apparatus, it is pushed over a main sealer comprising two units 360 and 361 (FIGS. 14 to 16) which are designed to seal the folded portions of the film underneath the article. The supports 341 and the end folding members 353, and the two units 360 and 361 of the main sealing apparatus are laterally adjustable by turning the hand wheel 186 so that the operator of the machine my adjacent the lateral distance between the two units of the main sealing appartus 361 to cause each side of an article to travel through one of the two units. Each unit of the main sealing apparatus 261 comprises the heating element 362 and an endless belt 363 which is trained around rear and forward rollers 364 and 366. The rollers 364 and 366 are located in longitudinally spaced relation at opposite ends of the longitudinally extending heating element 362, and the upper portion of the belt 363 rests on the upper surface of the heating element 362 and is pushed forwardly during operation. The belt 363 is not positively driven by the rollers 364 and 366, but it depends upon frictional engagement with an article for movement in the clockwise direction as seen in FIG. 15.

' With reference to FIGS. 14 and 15, the heating element 362 of each unit is shorter than the distance between the associated rollers 364 and 366, and between the rearward end of the heating element 362 and the rear roller 364 is located a plate 367. The upper surface of the plate 367 is in the plane of the top of the heating element, and when the belt 363 is turned in the clockwise direction as seen in FIG. 15, each portion of the belt 363 first travels around the rear roller 364, then over the upper surface of the plate 367, and then over the upper surface of the heating element 362. The provision of the plate 367 is advantageous because it prevents the portion of the film at the forward end of an article from being burned by the heating element 362. If the plate 367 were not provided and the heating element 362 extended to a location adjacent the rear roller 364, the portion of thebelt 363 adjacent the rear roll er 364 would became heated by; the heating. This heated portion of the belt 363 would'be engaged by the forward end of a package traveling in the forward direction, and the forward end of the package would tend to slide over the belt until the frictional engagement between the package and the belt 363 Wouldcause the belt 363 to turn. Such sliding rnovement over a heated portion of the belt might result in burning of the film at the forward end of the package. However, this possibility is eliminated by the plate 367: which is relatively cool as compared with the heating *element 362. A package moving in the .forward direction travels over the rear roller 364 and then on. to the plate 367, and by the time the article reaches the heating element 362. the belt 363 is turiiing. The plate 367 is heated somewhatby the adjacent heating element 362, and consequently the film at the forward end of the article is gradually heated by first traveling over the plate67 and then on to the heating element.

The belt 363 may be made of Teflon impregnated glass cloth which i able to'iwithstand the relatively high temperatures encountered and has little tendency to stick to the film.

To hold the side edges of a package tightly against the upper surfaces of the belts 363, a plurality of rollers 371 are provided for each the units of the main heater 36 1. Each of the rollers, in the present instance seven rollers being provided for each of the heating units, is similar in construction and operation to the rollers described in the previously mentioned Hansen et ai. patent applioation. Each roller 371 is rotatably: mounted on a link 372 which angles downward, forwardly, and l aterally. inwardly of the machine shown in FIGS. 15 and 16. A pin 373 rotatably connects the rollers 371 to the link 372, and another .pin 374 pivotally connects the link 372 to a stationary support 376, and still another pin 377 (FIGS. 15 and 16) is provided which limits the extent of clockwise (FIG. 15 pivotal movement of each link 372. When a link 372 is resting on the pin 377 the lower side of the associated roller'371 is located adjacent the upper surface of the belt .563. However, when a forwardly moving package engages the rear of the roller 371 and pushes it forwardly, the link 372 swings on the pin 374 in the counterclockwise dire-etion as seen in FIG. 15, and the roller 371 rotates in the counterclockwise direction: Each roller, which is relatively heavy, rolls along the upper surface of the article at the longitudinallyextending side thereof, and the weight of the rollers holds the article tightly against belt 363. After an article has passed underneath a roller 372, the roller and the link-372 swing downwardly until the link 372 again'engages the pin 377.

g A heat sink 381 is also providedazin each unit to cool the heated portions of the film before pressure on the article has been released by the rollers 371. When an article travels over the belts 363, the folded portions of the plastic film at the sides of the article become suffi- 'ciently heated to cause them to fuse together. However,

it is important @at pressure be mainained on the folded portions of the film until the film has cooled, otherwise the seal may be lost. Each heat sink 381 comprises a n longitudinally extending upper surface 382, located in the plane of the plate 367 and the heating element 363 and a plurlity of heat radiating fins 383 on the lower side thereof. The dimensions of the heat sink 381 are suchthat the folded portions of the film at each end of the article are cooied to a point where the fused film sets and maintains a good seal before the article passes out from under the last of the rollers 371. 1 A main sealer including two laterally spaced heating units as described advantageous as compared with a single heating unit which extends laterally acress the path of a package because there is no tendency to burn the portions of the film at the center of an article. There a b d 1 p of film underneath each nf the longitudinally extending sides of an article due to the end folding opera tion previously described, whereas a the center of the package on the underside thereof, there is only a single thickness of the film except where the ends 'of the filin overlap. Thus, if the main sealer extended laterally across the path of an article and were hot enough to seal the film at the sides of the article, it would. also have to be hot enough to burn the film at the center of the article, By providing two laterally spaced heating units in accordance with this invention, the heater may be made sufliciently hot to seal the folded portions of the film at the iongitudinally extending sides of the article without danger of burning the portions of the film at the center of the articlef 7 25 At the forward end of the transport mechanism 119 is provided a downwardly inclined chute or conveyor 386 (FIG. 1). The' transport arms 342 push the articles onto the upper end of the conveyor 382 and the articles either slide 'or are pushed down the conveyor 382 to a bin, for example, or to a transfer and labeling machine for weighingand applying labels to the articles.

The operation of the wrapping ma'ehine will now be described with particular reference to the timing diagram shown in FIG. 17. An operator of the machine places a series of articles on the input conveyor 36 between the flights or pushers 43, and the timing of the machineis slich that when the elevators 82 and 83 are in their vertically displaced positions, shown in FIG. 3, a pusher 43 pushes an article on to the bottom elevator 82;. Thereafter, the elevators 82 and 83 swing to the intermediate positions wherein the plates 116 and 117 are horizontally aligned and a section of the film 61;is suspended from the roller 74 and held by the baffle 84. The dancer roller 81 is moved upwardly by the lifts 256 and held there out of the path of the article. The bottom plungr 122 is then moved rearwardly of the machine causing the fingers thereof to engage the forward side of the article and push the article rearwardly under the dancer roller and against the suspended section of the film 61. As the article slides onto the plate 117 of the' top elevator 83 the fingers 192 are held in retracted positions and the rearward side of the article pushes the film against the friction pad on the receiver bar 146 of the top elevator and the filmfis thus held between the article and the receiver bar. Continued rearward movement of the article pushes the'receiver bar 146 rearwardly and as soon as the article is moved entirely onto the top elevator 83, the finger 212 engages the trip"'211 and'causes the fingefs 192 to snap upwardly. The two elevators 82 and 83 then swing in the clockwise direction to the vertically displaced positions shown in FIG. 3. The dancer roller 81 also moves downwardly and the film is drawn across 'the upper side of the article and then downwardly underneath the dancer roller 81 which is then being supported by the movable stops 258.1 I a With reference to FIG. 17, just before 'the elevators 82 and 83 reach their vertically displaced positions, the upper or top plunger 121 and the bottom plunger 122 begin to move toward the right, the bottom plunger 122 thereby making room for another articie to be placed on the bottom':elevator 82. The upper or top elevator 83 arrives at the uppermost position at 2 after the beginning of a wrapping cycle and the top elevator remains up until .of the wrapping cycle. While the top plunger 121 is moving forwardly the movable blades 'ef the film severing device begin to cut the film 44 of the first part of the;cycle. Between 44 and 74 the film is severed, and since the upper plunger does not stop until of the cycle, it will be apparent that the film is completely severed while the top plunger 121 is still pushing the article forwardly. While the article is moving forwardly and the film is being severed, the tack sealer wire 317 begins its 'upward movement, and after 80 of the cycle the wire is completely up and engages the underside of the article. The article then remains over the tack sealer while the top elevator 83'is moving downwardly again,

17 and after 175 of the cycle the tack sealer begins to move downwardly. Almost simultaneously with the beginning of downward movement of the tack sealer, a pair of the transport arms 342 move around and begin to push the article toward the right through the end folding and main sealing mechanism.

Going back to an earlier portion of the cycle, as soon as the top elevator has moved to the uppermost position, the fingers 192 are retracted by engagement of the portion 203 with the actuator 202, permitting the top plunger to push the article off of the plate 117. Also, as soon as the film is severed the movable stops 258 are retracted and the dancer roller 81 drops downwardly and slaps the severed end of the film on top of the baffle plate which then holds the film in preparation for the next wrapping cycle. The location of the movable stops 258 and the dancer roller while the film is being severed i such that the length of film extending from the roller 74, underneath the dancer roller 81, and up to the cutting blades has the proper length for the wrapping cycle. When the bottom plunger or pusher'122 moves in the rearward direction to push an article on to the top elevator, it extends a short distance over the plate 117 of the top elevator. This is necessary because the article must be pushed sufiiciently far onto the top elevator so that the fingers 192 may extend over the forward side of the article and so that the forward side of the article will not catch on the underside of the cutting blade 221 and the tack sealer when the top elevator moves upwardly. Since the bottom plunger 122 would interfere with the upward movement of the top elevator if the plunger 122 were to remain in this position, from 260 to 290 of the wrapping cycle the plungers 121 and 122 are moved forwardly sufficiently far to get the bottom plunger out of the way of the top elevator 83. As noted on the timing diagram, the plungers retract immediately after stopping their rearward movement, without a dwell in their rearwardmost positions. The plungers then remain stationary while the elevators are moving to their vertically displaced positions, and then the plungers move forwardly as previously explained. The foregoing forward and rearward movements of the plungers, and the dwells are of course produced by the shape of the cam 52 connected to the mechanism 54. This cam is also shaped such that, during the forward movement of the plungers when an article is being pushed from the top elevator, the plunger first accelerate relatively rapidly and then decelerate at a relatively constant rate. The velocity of the top plunger reaches a relatively high rate at the first part of the forward movement and, after the peak velocity, the top plunger slows down such that its speed at any instant is slightly greater than the speed an article would have if the article were sliding freely. Therefore, the top plunger is in constant contact with the article until the article stops, and there is no danger that the article will slide forwardly ahead of the top plunger.

After the article has been moved from the top elevator onto the the support 118, it is picked up and pushed by the transport arms 342 through the end folding mechanism. After the ends of the film have been folded underneath the article, the article is pushed over the two units of the main sealer. The forward sides of the article first travels over the rollers 364 and then over the relatively cool plates 367, the rollers 371 pressing the article downwardly against the belt 363 with sufiicient force to cause the article to push and turn the two belts 363. The article and the upper portions of the belts then move forwardly, and the article passes over the two relatively hot heating elements 362. The heating elements 362 are sufiiciently hot that the folded portions of the films at the ends of articles are heated to fushion temperature, and subsequently the transport arms 342 push the article from the heating element 362 and over the heat sinks 381. The heat sinks 381 are relatively cool as compared with the heating element 362, and they cool the heated portions of the film sufliciently to set the heated portions of the film while the article is still under pressure by the rollers 371. The tightly wrapped and sealed package is then pushed by the transport arms 342 onto the output conveyor 386 where it may be transferred, for example, to a transfer and labelling machine.

We claim:

1. A wrapping machine for wrapping an article in a protective film, comprising a film supply and feed mechanism for supplying film, a wrapping mechanism for folding the film lengthwise around the article, and a mechanism for folding the film at the ends of the article and sealing the film, said wrapping mechanism comprising a plate, means for moving an article in a rearward direction on to said plate and causing said article to rest on the free end of the film, means for moving said plate to cause a portion of the film to fold longitudinally across one side of the article and over the top of the article, retractable means at the forward edge of said plate for holding an article on the plate while the plate is moving, trip means engagable with said retractable means for holding said retractable means retracted while the article is being moved on to said plate, and release means for contacting said trip means and causing said trip means to disengage said retractable means immediately after an article has been moved on to said plate, whereby said retractable means extends to hold the article immediately after the article has been moved on to the plate and before the plate begins to move, said release means being connected to and moving with said means for moving an article on to said plate.

2. A wrapping machine for wrapping an article in a protective film, comprising a film supply and feed mechanism for supplying film, a wrapping mechanism for folding the film lengthwise around the article, and a mechanism for folding the film at the ends of the article and sealing the film, said wrapping mechanism comprising a plate, means for moving an article on to said plate and causing said article to rest on the free end of the film, means for moving said plate to cause a portion of the film to fold longitudinally across one side of the article and over the top of the article, means for moving the article off the plate and causing the film to fold across the opposite side of the article, means for severing the film at a location where the ends of the section of film around the articles overlap, and means for tack sealing the overlapping portions of the film, said tack sealing means comprising a relatively small heated member which is mounted for vertical movement below the path of the article as the article is moved off of said plate, said heated member being movable between a first position where it engages and seals said overlapped portions of film and a second position where it is below and out of engagement with the film, said heated member being supported by pivotal means located substantially midway between the ends of said heated member, said heated member being pivotable about said pivotal means whereby said heated member may conform to the plan-e of the underside of an article.

3. A wrapping machine for wrapping an article in a protective film, comprising a film supply and feed mecha nism for supplying film, a wrapping mechanism for folding the film lengthwise around the article, and a mechanism for folding the film at the ends of the article and sealing the film, said wrapping mechanism comprising a plate, means for moving an article on to said plate and causing said article to rest on the free end of the film, means for moving said plate to cause a portion of the film to fold longitudinally across one side of the article and over the top of the article, means for moving the article off the plate and causing the film to fold across the opposite side of the article, means for severing the film at a location where the ends of the section of film around the articles overlap, means for tack sealing the overlapped portions of the film, said tack sealing means comprising a relatively small heated member which is mounted for vertical movement below the path of the article as the article is moved off of said plate, said heated member being movable between a first position where it engages and seals said overlapped portions of film and a second position Where it is below and out of engagement with the film, and a spring connected to each end of said heated member for retracting said heated member from said first position.

References Cited UNITED STATES PATENTS Kottmann 53-210 Prince 53-379 X Littlefield 5321O Bartlo et a1 53379 Rundell 53388 Asbury.

N. ABRAMS, Assistant Examiner US. Cl. X.R. 

